Although barbed wire was originally devised as a fencing material to control grazing livestock, it has also come into commonplace use as a defensive security barrier to inhibit human intrusion. Typically, the barbed wire is strung atop a fence or wall on obliquely upstanding outriggers to discourage people from climbing over the fence or wall. The barbed wire may also be secured in helical loop fashion atop a fence or wall for the same purpose.
The use of barbed wire in such a manner is a psychological barrier as much as physical barrier, due to the fact that there are many ways to circumvent the barbed wire barrier. For example, the wire easily may be cut by manual tools, or the wire may be covered with a heavy blanket, a piece of wood, or the like, to neutralize the barbs and provide access thereover. Furthermore, the outriggers which support the barbed wire strands may actually encourage breachment of the wall or fence by providing handholds at the top of the wall or fence for the person attempting to climb thereover.
In more recent years, there have been developed other materials to overcome the deficiencies of barbed wire noted above. These materials and devices generally comprise elongated metal strips having sharpened edges and/or sharpened barbs extending outwardly therefrom. Generally speaking, these metal strips are formed in helical loops and are placed atop a fence or wall. Although these materials are more effective than barbed wire, they are also extremely expensive to manufacture, due to the greater amount of material used in the metal strip, and also due to the helical loop configuration of the metal strip. Also, these prior art materials have been shown by experience to be extremely difficult to manipulate and to install, due to the sharp edges and sharpened barbs. Also, these devices have exhibited difficulty in installation due to the barbs and their tendency to become entangled. The entanglement of the prior art material is further exacerbated by longitudinally extending wire elements which are secured to adjacent helical loops to prevent spreading thereof. A prior art patent which discloses a typical material is U.S. Pat. No. 3,463,455, issued on Aug. 26, 1969.